If he's lying down, don't let him lie down on one side too long. That's not good for his lungs.
Put a towel under his chest and gently lift him to his feet and walk him around from time to time.
We have a 110-pound black lab. He often has symptoms exactly like you’ve described. They come and go - most often if he manages to get into something chocolate. Our vet in Naples told us that epilepsy in not uncommon in labs. His symptoms are usually ver short-lived, we’ve never managed to get him to a vet before they pass. Usually we have to carry him outside and help him stand until he can poop. Once he poops he seems to get better. He’s never had one of his seizures last more than a few minutes though. We even rushed him to a vet emergency room once but by the time we got there he was fine so we have no definitive answer. A vet is the best choice, somehow, somewhere. My heart goes out to you because when our dog is going through this it is a pathetic thing and he runs to me expecting that I’ll help him and I’m unable to do much for him.